Title On the Rejection of Reason by the Early Empiricist Author(s) Nishimura, Seishu Citation 京都大学文学部哲学研究室紀要 (2005), 8: 160-170 Issue Date 2005-12-10 URL http://hdl.handle.net/2433/24239 Right Type Departmental Bulletin Paper Textversion publisher Kyoto University On the Rejection of Reason by the Early Empiricist Seishu Nishimura In his “On the Sects for Beginners,” Galen describes a debate between two primary sects of medicine in antiquity: the empiricist and the rationalist. According to Galen, “medicine is the science of what is healthy and what is unhealthy,” by virtue of which the doctor can prescribe the remedy (SB, 1).1 In this sense, medical knowledge is essentially practical. But the empiricist and the rationalist disagree over the origin of such knowledge. The former claims that “experience alone” is sufficient in order to obtain it (ibid). We will call this the empiricist claim. Roughly speaking, by “experience,” the empiricist means perception and memory. There are three types of experience by which we can acquire medical knowledge: (i) “autopsia,” i.e., one’s own perception, (ii) “history,” i.e., one’s knowledge of the experiences of others, and (iii) “the transition to the similar” (SB, 3).2 Here, (ii) and (iii) supplement (i) because firsthand experience is a limited capacity. The core of the empiricist claim is that, given the experience gained in these ways, we don’t need any other things for medical knowledge. For the empiricist, X is medical knowledge if X is obtained from and confirmed by experience. On the contrary, the rationalist insists that, in addition to experience, the use of “reason” is necessary for medical knowledge (SB, 1). According to this school, the doctor needs theoretical knowledge obtained by reason in order to distinguish herself from the layman who knows some remedies just from experience. To this end, the rationalists appeal to the nature of matter, which is unobservable to us, as the cause of the observable symptoms when they explain what kind of remedy to prescribe. 160 On the Rejection of Reason by the Early Empiricist For the discovery of this hidden real cause, they rely on reasoning from what is manifest to what is not manifest. For them, X is medical knowledge only if there is a justification for X from the theory concerning the unobservable nature of the body. Now, there is a problem for the empiricist on its rejection of the use of reason. The problem is that even the empiricists seem to use a kind of reason when they form medical knowledge.3 According to them, after observing similar experiences sufficiently many times, we can form “a memory” such that when we give a particular kind of remedy if we observe a particular kind of disease, this result will follow (SB, 3). This memory is called a “theorem” and constitutes a crucial part of the medical art (ibid). Here, by grasping such a similarity, the empiricists must have a general belief that we can prescribe a remedy for this kind of disease. But to have such a belief, the empiricist seems to use a form of inference from particular cases. But we should not rush to the judgment that the empiricist is therefore inconsistent. There are a couple of difficulties for interpreting what exactly the empiricists mean by the empiricist claim. First, we have to make explicit what they reject as “reason.” If the notion of reason that they reject is peculiar to the rationalist, then the reasoning which the empiricist seems to use may not fall within the scope of its rejection of “reason.” Second, we cannot regard empiricism as a unified doctrine. There are some differences in the attitude towards the use of reason among the empiricists. In this paper, we shall reconstruct the epistemology of one of the stronger positions of the empiricists, and examine whether it can maintain the empiricist claim consistently. We should start by elucidating what the rationalist notion of “reason” is. Although there is no unity among the rationalists, essentially, the rationalist reason is a theoretical reasoning with regard to the unobservable. We can point out two kinds of this reasoning. First, “reason” is the deductive inference from the general proposition about the nature of bodies to the propositions about particular states of body and their remedies. The rationalist method for medical knowledge is to obtain necessary truths by the deduction of remedies from the causes of diseases such as “the nature of body,” “airs, waters, places, occupants, foods, drinks, and habits” (SB, 161 4). The rationalist calls the relationship between the observed symptom and its remedy “indication” (ibid, 5). Behind this indication, there underlies deductive inference from the theory of the nature of body. Second, “reason” covers inductive inference to go from the observable to the unobservable by forming the theory of the nature of body. For example, Galen reports that, for the discovery of the nature of bodies, the rationalists use “anatomy” in addition to “indication and logical theory” (ibid, 10). Anatomy requires the observation of the structure of dead bodies. From this observation, the rationalists analogically infer how our bodies work when they are alive. All the empiricists show almost the same argument against the rationalist “reason.” Roughly speaking, however, we can distinguish two different attitudes of the empiricist towards a kind of reason. One is an early empiricist who denies any use of reason for the discovery of remedies. We shall call this position strong empiricism (SE). The other is a later empiricist which is weaker in the sense that it admits the use of reason with regard to what is observable (OE, 88). This type of reasoning is called “eplilogism” (ibid, 133). Epilogism is “an inference common and universally used by the whole of mankind, and wherein men are unanimous,” and it refers to visible things alone (ibid).4 Let’s call this second position weak empiricism (WE). Both SE and WE reject the rationalist “reason” for an epistemological reason. As we have seen, the rationalist uses inference from and to what is unobservable. SE emerged as a reaction to this trend. It claims that the rationalist is wrong because we cannot obtain true theoretical knowledge. SE is dogmatic in that it claims the unknowability of the unobservable. Sextus says that the empiricists before the emergence of Pyrrhonism are not skeptical but dogmatic in that they affirm “the inapprehensibility of unclear matters.”5 From the chronological viewpoint, this type of empiricism should contain SE. For SE, what we can know is restricted to the observable (SB, 14). Thus, the rationalist use of inference is wrong because there is no epistemological guarantee for the reasoning concerning the unobservable. Any theoretical knowledge is not “true” however “plausible” it may be (ibid, 10). As its 162 On the Rejection of Reason by the Early Empiricist evidence, despite the claim that the true causal account was required for knowledge, there was no agreement on what such knowledge would be among the rationalists.6 WE also denies the use of theoretical reasoning because it is concerned with what is unobservable. But WE is not dogmatic like SE, rather skeptical in the sense that it claims the suspension of judgment concerning what is unobservable (ME, p. 136). Thus, the WE doctor doesn’t commit herself to the investigation of the nature of bodies. She only admits inference from what is observable to what is unobservable “temporarily” (SB, 11).7 SE and WE differ in the fact that the former denies even the inference just concerning what is observable while the latter admits it. SE holds that perception and memory will sufficiently provide medical knowledge (OE, 87). On the contrary, WE admits that the process that we engage in to know which remedy to prescribe is an “inference,” i.e., epilogism (ME, 133). In ME, Galen compares the rationalist to WE concerning how to obtain remedies. While the rationalist appeals to the deductive inference from the causes of disease in order to derive them, the WE doctor knows the same remedies in terms of inference from the belief obtained by the similar experiences (ibid, 136-9). According to Galen, epilogism is introduced by Menodotus, a WE doctor, as “something third” in addition to perception and memory (OE, 88). The context in which Galen mentions him is discussing whether we really don’t need any use of logical reasoning for knowledge, and Galen criticizes SE by saying that perception and memory are not sufficient (ibid, 86-90). Thus, it is natural to regard epilogism as something logical compared to memory and perception. Although we cannot obtain necessary truths from epilogism (because it just relies on empirically generalized theorems), each step of it is logical in the sense that we derive the conclusion from general beliefs as premises and a particular observation. But SE never admits that we have to use such an inference for knowledge. In fact, some extreme SE doctors deny the existence of “proof” in general (SB, 10). For SE, everything should be done solely by perception and memory. In the following, we shall reconstruct the epistemology of SE and examine how SE can support the empiricist claim against the criticisms from the rationalist. 163 Since SE holds that perception and memory sufficiently provide medical knowledge, we should elucidate SE’s notions of perception and memory in order to reconstruct its epistemology. In general, the empiricist regards perception as the only way of recognition. In fact, according to Galen, experience is defined as “the knowledge of something which is based on one’s own perception,” i.e., on autopsy (OE, 44). But this definition is not sufficient.